Department of Chemistry, University of Toronto, 80 St. George St., Toronto, ON M5S 3H6, Canada.
Dalton Trans. 2019 Oct 14;48(38):14242-14245. doi: 10.1039/c9dt03185e. Epub 2019 Aug 27.
Reactions of RC[triple bond, length as m-dash]P (R = tBu or Ad (admantyl)) with NHCs (SIMes, 1a; IMes, 1b and IDipp, 1d), leading to 1,2,3-triphosphetenes 2 and 3, a triphosphole 4, and a di-1,2-dihydro-1,2-diphosphete-substituted diphosphene 5, are reported. Compound 5 represents a novel P chain framework, as well as a newly discovered phosphaalkyne hexamer stabilized by two NHCs. Computational investigations suggest that the weak π-accepting ability of NHCs results in low stability of the initially formed 2H-phosphirenes, thus facilitating spontaneous oligomerization reactions. Such oligomerizations are highly susceptible to the electronic property and steric bulk of NHCs.
报道了 RC[三重键，长度为破折号]P（R = tBu 或 Ad（金刚烷基））与 NHCs（SIMes，1a；IMes，1b 和 IDipp，1d）的反应，得到了 1,2,3-三磷烯 2 和 3、三磷杂环戊烯 4 和二-1,2-二氢-1,2-二磷杂环戊烯取代的二磷杂环戊烯 5。化合物 5 代表了一种新型的 P 链骨架，以及一种由两个 NHC 稳定的新发现的膦炔六聚体。计算研究表明，NHC 的弱 π-接受能力导致最初形成的 2H-磷烯的稳定性低，从而促进了自发的齐聚反应。这种齐聚反应非常容易受到 NHC 的电子性质和空间位阻的影响。
